La Palma is one of Spain’s Canary Islands, a beautifully rugged bolthole just off the coast of Africa that has attracted tourists for years.
It is a volcanic island at its heart, dotted with such natural openings in the Earth’s crust.
Unlike many islands around the world, two of these volcanoes are active and have in modern times erupted multiple times in recent years.
Because of their geological makeup and proximity to the sea, some volcanologists warn that future eruptions risk collapsing significant material into the surrounding ocean and sparking what one scientist described as a ‘megatsunami’.
La Palma is a relatively new island having only sprung into existence three million years ago — a baby in the world of rock formations.
It is therefore vulnerable to fast-flowing landslides in the event of an eruption, something which was explored during Naked Science’s documentary on natural disasters.
Speaking of a volcanic event on the island, the documentary’s narrator noted: “A slide from this mountain could kill millions of people in Europe and along America’s eastern seaboard.”
Cumbre Vieja has a long history of violent activity and has erupted at least eight times since the Spanish began keeping records in the 15th century.
Over time, these eruptions have created steep-sided cones on which thick layers of ash and residue rest, precariously balanced.
Professor Bill McGuire, a geologist at University College London (UCL), has studied La Palma’s volcanic ridge and believes the build-up of gas beneath its surface could in the future lead to a considerable eruption.
The pressure from the gas would manifest itself in the form of fissures, opening a lengthy fault line straddling the entire island.
This fault line runs for at least nine miles, and Prof McGuire believes that if it were to burst open after an eruption, around 500 billion tonnes of rock would pour out into the neighbouring Atlantic Ocean.
This landslide could reach a speed of more than 220mph. “It would be hurtling down the slope of the volcano; it would start to break up into smaller pieces into the ocean,” he said.
“By then it would already have displaced something like half a mile of water which would be towering above your head, and that would probably be the last thing you’d ever see.”
On impact with the water, a dome 3,000 feet high would shoot into the sky, forming what Prof McGuire described as an “Oceanside tsunami”.
“[It would be] at least as devastating as those that struck the Indian Ocean,” he said.
Predictive models suggest that the waves would have the potential to travel up to 4,000 miles towards the US east coast.
While the waves would lost much of their power by the time they reached the US, “they would travel all the way across the Atlantic Ocean to the east coast of North America”.
